The invention relates to detonators for use with explosive devices.
Explosive devices such as shaped charges in perforating guns are commonly used in a well to create openings in a casing section and to extend perforations into a surrounding formation to allow communication of fluids between the formation and the well surface. Explosives may also be used to activate downhole tools, such as packers. Other types of explosive devices include those used in mining operations and other surface applications.
Detonators used with explosive tools are of two general types: electrical and percussion. An electrical detonator may also be referred as an electro-explosive device (EED), which may include hot-wire detonators, semiconductor bridge (SCB) detonators, or exploding foil initiator (EFI) detonators.
An EFI detonator includes an electrically conductive metal foil connected to a source of current. The metal foil includes a narrow neck section that explodes or vaporizes when a high current is discharged quickly through the neck section. The exploding neck section of the foil shears a small flyer from a disk that is disposed in contact with the foil. The flyer travels or flies through a barrel to impact a secondary explosive to initiate a detonation.
A conventional EFI detonator typically includes a capacitor discharge unit of relatively large size, which leads to increased sizes for housings in downhole tools for containing such detonators. Further, because of their relatively large sizes, the efficiencies of conventional EFI detonators are reduced due to increased resistance and inductance of electrical paths in the detonators. As a result, higher voltages and power may be needed for activating such detonators. A need thus continues to exist for improved EFI detonators.
In general, according to one embodiment, a detonator assembly for use with an explosive device includes a support structure, an exploding foil initiator mounted on the support structure, and at least another component mounted on the support structure. An opening formed in the support structure adjacent the exploding foil initiator, with the opening adapted to receive an initiating element of the exploding foil initiator.
Other features and embodiments will be apparent from the following description, the drawings, and the claims.